Special code used on Chevrolet Camaros to indicate that they are
equipped with the racing performance package. This package deletes
air conditioning and several other luxury items and beefs up the
suspension. The 1LE intake elbow is useful for Impala engine
modifications

Chevrolet order code for the police package option on the Caprice.
This is usually used to refer to parts that only come as part of
this package, such as "9C1 Trunk Mat".

ABS

Acronym for Antilock Braking System. This system prevents the
tires from "locking up" under heavy braking or slick conditions by
modulating pressure to the brakes when sensor determine that the
tire is no long rolling. This allow quicker, straighter stops in
most conditions than standard braking.

Acronym for assembly line diagnostic link. This is the small black
connector underneath the driver's dash. This connector allows the
dealer to plug in scan tools to test and report the status of the
PCM. This is how the dealer scans for trouble codes. This is also
how the PCM can be reprogrammed.

Acronym used by owners of black Impalas who feel left out because
they don't have a cool acronym like DCM or DGGM to use. Actually,
the official GM name is Standard Onyx Black, but that isn't used
for obvious reasons. Usually taken to mean Bad to the Bone Black.

Acronym for Blue Bow Tie. This is a part from the 97 Cavalier that
will drop into the same place the silver bow tie on the front of
the Impala grill is from the factory. It seems to look better on
the DGGM Impalas than the red bow tie.

Acronym for Brake Transmission Shift Interlock. This is a solenoid
that prevents you from shifting out of park unless your foot is
pressing on the brake pedal. This is touted as a safety feature,
but is commonly thought to be a direct result of the lawsuits
filed by some Audi owners claiming "unintended acceleration" of
their cars when they were started.

Acronym for Center High Mounted Stop Lamp, which is the third
brake light located at the bottom of the rear window.

Clear Flood Mode

A special starting mode that allows for clearing of excess fuel in
the engine. It is made to emulate the method for clearing floods
in carburated cars. The throttle must be depressed to 80% or more.
The PCM will then lean the air/fuel mixture out to 20:1 to clear
the flood. Clear flood mode is automatically shut off when engine
RPM is greater than 300 RPM.

A general classification of mechanisms designed to get cooler air
from outside the engine compartment into the engine intake tract.
This is usually accomplished by some sort of scoop or ducting to
the outside.

CRBT

Acronym for Cavalier Red Bow Tie. This bow-tie is a drop-in
replacement for the bow-tie on the grill of the stock Impala.

Acronym for Daytime Running Lights. This GM option turns the
headlights on at a reduced voltage during all operating
conditions. During nighttime operation, the headlights are
brightened and the rest of the running lights and the tail lights
are also turned on. This option is required in Canada, but can be
fitted to US models. This option is technically not compatible
with the Twilight Sentinel, but you do get the basic twilight
sentinal functionality. The front lamps just don't go off during
daylight hours. On pre-1996 cars, the light sensor was not
included with the package, so the tail lights had to be turned on
manually at dusk.

Acronym for Engine Coolant Temperature. This sensor is mounted in
the coolant pump and sends engine temperature information to the
PCM. The sensor is a thermistor that changes internal resistance
as the temperature changes. When the resistance is high, the PCM
interprets that the engine is cold. When resistance is low, the
voltage through the wire will decrease and the PCM will interpret
it as a warm engine. The ECT is located on the front of the
engine, just below the water pump.

Acronym for Electronically Erasable Programmable Read Only Memory.
This is more commonly referred to as flash memory. This type of
memory is to store the engine control parameters in the PCM. The
EEPROM in the PCM can be reprogrammed using the Tech-1 scan tool.

Acronym for Exhaust Gas Recirculation. This sytem reduces
emissions, specifically Nitrogen Oxides caused by high combustion
temperatures and excessive oxygen. It does this by decreasing
combusion temperatures and displacing oxygen with spent exhaust
gases. The main element is the EGR valve mounted on the intake
manifold and operated by vacuum.

Abbreviation for the Evaporative Emmisions Control System. This
system utilized a charcoal canister to hold vapors from the fuel
tank while the vehicle is not operating. When the engine is
running, the vapor is purged from the canister into the normal
intake path and consumed in the normal combustion process.

Flash memory is a non-volatile form of read-only memory that is
used in the Impala to store the computer program that controls the
engine. It is located in the PCM. On earlier cars, this is known
as "the chip" and is commonly replaced with a higher performance
program stored on a different chip. On LT1 engines, the flash
memory is reprogrammed through the DLC, which is often referred to
as "flashing" the PCM.

Acronym for Green Grey Metallic, one of the available colors for
the Impala in 1995 and 1996. More commonly referred to as DGGM,
for Dark Green Grey Metallic, but GGM puts it into the TLA (Three
Letter Acronym) territory.

Acronym for the Hypertech Power Programmer. This device reprograms
your PCM with a custom performance program. You insert it through
the ALDL underneath you dash. It then reads the stock program out,
modifies it according to your parameters, and stores it back. You
can reprogram and deprogram your PCM at will.

Acronym for the Hypertech Power Programmer Plus. This device works
much the same way as the HPP, but allows more parameters to be
modified, and will eventually allow custom cartridges to be
inserted to function as scan tools and other functions. This is
the second generation of the HPP.

Acronym for Incoming Air Temperature. This sensor is mounted in
the elbow that connects to the throttle body and monitored by the
PCM. The PCM controls fuel delivery and spark timing based upon
the incoming air density.

Idle Air Control

The purpose of the Idle Air Control valve is to control engine
idle speed to prevent stalls based upon changes in engine load.
The IAC control is mounted in the throttle body and can bypass air
around it based upon PCM control.

IMHO

Acronym for In My Humble Opinion. Used in internet e-mail
correspondence to distinguish fact from opinion.

Acronym for Jet Assisted Take Off. The military uses JATO rockets
to assist in getting heavy planes off of the ground. There is an
urban legend about someone who strapped one to their Impala out in
the desert and then crashed into a cliff doing around 300MPH. The
story is a complete fabrication, and ends up being posted to the
Impala mailing list about once a month.

Acronym for the Mass Airflow Sensor. The MAF sensor used on the
Impala is the hot-wire type. The output frequency from the MAF is
a function of the power required to keep the air flow sensing
elements (hot wire) at a fixed temperature above ambient. As air
flow increases, a greater amount of current is required to keep
the wires at a constant temperature due to the cooling affect of
the increased quantities of air. The MAF is directional and must
be installed in the proper direction.

Acronym for Manifold Absolute Pressure. This sensor measures the
change in the intake manifold pressure as speed and engine load
changes. As the manifold pressure increases, the air density in
the intake manifold also increases.

Acronym for National Association of Impala SS Owners, a nationwide
organization of over 500 Impala SS Owners. Troy Wilrick
runs it from Florida, and there are many regional chapters
springing up all over.

Acronym for On-Board Diagnostics II, a system instituted by a
Federal standards committee that forces the engine control system
to be able to monitor for a failure in any sensor in the emmisions
control circuitry. This is only fully implemented on 1996 Impalas.
This required PCM changes and an extra set of oxygen sensors to be
fitted to 1996 Impalas.

The distributor ignition system on the LT1 engine. This system
utilizes an optical sensor to detect timinng pulses on the
crankshaft. The PCM then receives both a low resolution (4x) and
high resolution (360x) signal to control timing to the injectors.

Acronym for Pressure Control Solenoid. This solenoid allows the
PCM to vary the line pressure to the transmission to make shifts
crisper and harder based upon throttle position, engine RPM, etc.
This feature allows for aftermarket PCM programs to incorporate an
electronic "shift kit" without opening up the transmission.

Acronym for Purple Door Panels. Some Impala door panels come from
the factory with a purple tint to them. They tend to very: some
may have a definite purple color, others may be slightly tinted.
We are in the process of trying to get GM to issue an official TSB
on this issue, otherwise, you can take your chances on getting
your local dealer to replace them for you.

Acronym for Random Access Memory. This is the PCM's scratch pad.
The processor can read or write from this memory as needed. This
memory is erasable and requires battery power to be retained. If
the battery is disconnected, this memory is lost. The DTC's are
stored in RAM.

Acronym for Red Bow Tie. The red bow-tie has become the unofficial
symbol of NAISSO. It involves replacing or taping over the OEM
chrome bow-tie on the grill of the Impala. There is a nice unit
from the Cavailier that does it nicely. This is the only part of
Jon Moss's concept car that didn't make it into production.

A baffle meant to reduce noise in an air passageway. There are
several baffles on the Impala. The first is a black rectangular
piece after the air clean but before the MAF. The second is the
triangular black plastic piece that sits on top of the engine.
These two resonators serve to reduce air noise entering the
engine. There are also two exhaust resonators just before the tips
at the rear of the car. These serve to reduce exhaust noise.

Acronym for Read-Only Memory. There is permanent memory physically
soldered into the boards within the PCM. The ROM contains the
overall control programs. Once the ROM is programmed at the
factory, it cannot be changed. It is non-erasable, and does not
require battery power to be retained.

A chemical term used when both elements in a process are
completely used in a reaction. In this case, it refers to the
oxygen and the fuel being burnt in the engine. This air/fuel ratio
is usually 14.7:1.

Acronym for Torque Converter Clutch. The torque converter allosw
limited slippage inside of the transmission to allow the engine to
spool up into its power band quicker, and to allow the engine to
idle while still in gear. The TCC "locks up" via this clutch while
at highway speeds to reduce parasitic losses through the slippage.
Lockup is controlled via the PCM.

Acronym for Technical Service Bulletin. These are short papers
distributed to GM technician to help them diagnose and remedy
common complaints and problems. They are not the same as recalls,
which are done at no cost to the consumer and are usually only
performed for safety reasons. TSBs are usually covered under the
original warranty, if it is still in effect.

Acronym for Underhood Electrical Center. This is a black box that
is located near the firewall on the passengers side. Inside the
box you will find various fuses and relays, and beside it you will
find the auxiliary battery terminal.